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No abstract

ART. XXXI.-Optical Projection of Acoustic Ou•rves,. by W. LEOONTE STEVENS. THE following application of a well known principle may be of sufficient interest to teachers of Physics to justify its publication; it has not been elsewhere described, so far as is known to the writer. By appropriate measurements on paper the sinusoids representing the tones composing any group of musical sounds can be compounded, and the resultant curve represents the concord or discord produced. The construction of such curves involves much tedious work. Any of them may be easily produced and optically presented on a screen by a simple modification of the method commonly employed in projecting Lissajous' curves. Optical P1'esentation of a Concord.